Working tubular articles



Sept. 24, 1946. c, c, uc r 2,408,325

WORKING TUBULAR ARTICLE Filed Oct. 21, 1944 4 Sheets- Sheet 1 Flam- FlELi- 07 4/9155 C 14/65 m/ G Wm a pu/vmm Sept. 24,1946:

C. C. LUCIE ETAL WORKING TUBULAR ARTICLE File'd 001.21, 1944 4 Sheet s-Sheec 2 17206221015: (Hafiz 5 C 11/62 00d u/v Z 5 FIG. 5.

Sept; 24, 1946.

C. C. LUCE ET AL WORKING TUBULAR ARTICLE 7 Filed oct 21, 1944 fnumzzoxss 67/42455' C 1005 m/ A/E/L 5. DU/VCfi/V;

. p -2 ,19 6." f..'| uE- E' TAL 2,403,325

I WORKING TUBULAR ARTICLE x Filed Oct. 21,- 1944 4-She et sSheet 4 v [5 Q 1 v INIVENTORsE" 0142155 C ZUCE, an!

/V/L 5. Dwvcmy, 5x12 THEIR ATTORNEY.

Patented Sept. 24, 1946 UNITED STATE WORKING TUBULAR ARTICLES Charles C. Luce, McKeesport, and Neil B. Duncan, Pittsburgh, Pa., assignors to National Tube Company, a corporation of New Jersey Applicationoctober 21, 1944, Serial No. 559,866

It has heretofore been proposed to increase the yield strength of the threaded end sections of oil well casing and the like by cold WOIkiIl them prior to threading. Since cold working of itself will not give the required strengthin all cases, it is frequently necessary' to upset, i. e., thicken the walls by a hot forging operation, to give additional metal under the roots of the threads. Cold working of the standard internal upset joint has added materially to the cost thereof since in order to meet the close tolerances necessitated by operating conditions, it has been necessary to rough and finish machine the bore of 1 such joints. Moreover, because metal does not flow freely incold working, it has been necessary to perform the cold work- 4 claims. (01. 29156) Figures 8 and 9 are enlarged sections similar to Figures and 6, showing a modification.

held between dies 2 and by suddenly applying pressure against the end thereof by a mandrel ing in a, series of operations which in turn added to the cost of treating such joints. 1 I t It is accordingly an object of -the present .in'-- vention to provide an improved method of- -andapparatus for cold working the endsections of plpen g It is another objeotpto provide a method of and apparatus for producing thickened end sections on tubular articles that have been strength ened by a cold working peration. a

It is a further object to provide a method and the tensile properties thereof and to meet close dimensional tolerances.

It is a still further object to provide an improved apparatus for cold working tubular articles.

The foregoing and further objects will be apparent from the specification and drawings wherein:

Figure 1 is a longitudinal section of the end portion of a tube;

Figure 2 is a diagrammatic showing of the upsetting operation;

Figure 3 is a view similar to Figure 1 showing the tube after it has been upset;

Figure 4 is a similar view to Figure 2 showing the improved apparatus of our invention;

Figure 5 is an enlarged section of the dies and mandrel of Figure 4 and shows thedies of Figure 4 being moved over the upset end of the tube;

Figure 6 is a view similar to Fig-ure 5 but shows the position of the dies when being withdrawn from the upset end of the tube;

Figure 7 is a sectional view similar to Figures 1 and 3 showing the tube section after it has been cold worked by the apparatus of 4,5and 6; and V V apparatus forcold workingpipe ends to raise or punch 3 to shorten the-workpiece and thicken and taper the walls thereof as shown in Figure 3. The mandrel or punch 3 may be activated by a suitably operated crank 4.

-- In Figures 4, 5 and 6, we have shown a pre-'v ferred embodiment of our improved apparatus for cold working tubular articles designated gen-,

erally by the letter C. This comprises a die body I I mounted on'a connecting rod or carrier- 8 connected to a crank 6 by a pitman 9 and acrosshead 5. b

An annular filler member 12 and working die:

member l4 are secured tothe die body H by bolts IS .with the joints therebetween rabbeted as at 13. Theinner surface of the die Id-has" a central flat portion 16 and curved or inclined portions l1 and I8 leading therefrom.

A mandrel 20 is secured in the diebody-H by a. screw threaded connection 2i providing an annular space 22 therebetween and has a reduced diameter portion 23 and shoulder 24 adjacent the outer end thereof; A sleeve or die member 25 'of less length than the reduced'portion 23 is mounted thereon with a lost motion slidable connection and held thereon by nut: 26., The outer surface of the die member 25 has a central flat portion 21 and curved or inclined portions 28 and 29 leading therefrom.

A chuck or gripper 30 is provided in alignment with the cold reducing apparatus C to 7 hold the workpiece A rigid while it is expanded and reduced thereby.

In practicing the teachings of our invention, the tubular workpiece A is heated to a suitable forging temperature of the order of 2200 to 2400" F. and then upset in the upset press B wherein the length thereof is shortened and the walls thickened and provided with a slight inside taper. The workpiece A is then permitted to cool and is placed in position in front of the cold. work apparatus C and securely gripped in the chuck 30. Crank 6 is set in motion to move the cold Figures abuts the shoulder 24. The inclined face 28 thereof then operates to expand the diameter of the workpiece A as it is moved into the annular space 22. As soon as all the thickened portion of the workpiece has been expanded, crank 6 is operated to reverse the travel of the cold working apparatus C to move in the direction shown in Figure 6. The sleeve 25 is held stationary by frictional engagement with the workpiece until the mandrel rod 20 moves outwardly far enough to bring the nut 26 into engagement therewith. This brings the flat working faces I and 21 of the dies l4 and 25 into opposed relation, and upon continued movement thereof, the diameter of the workpiece is reduced by the die l4 and the wall thickness thereof by the conjoint action of the die 14 and the sliding die 25.

As shown in Figure '7, when the dies !4 and 25 have passed completely over the workpiece, the outer diameter thereof has been returned to its original dimension and the wall which was thickened and tapered in the upset press B has been reduced to a uniform thickness, the inside walls being concentric with the axis of the pipe so that it is unnecessary to machine the inside diameter thereof.

In Figures 7 and 8, there is shown a modification wherein the cold working is done with the outer die member l4 mounted with a lost motion slidable connection on a tubular element 311 which is secured to the die body I! by bolt l5 and the annular filler member l2. A collar 31 may be interposed between the end of the bolt and the tubular .element 36. In this modification, the inner die member 25' is fixedly mounted on the mandrel 20.

While we have shown and described one specific embodiment of our invention, it will be un derstood that this embodiment is merely for the purpose of illustration and description and that various other forms may be devised within the scope of our invention, as defined in the appended claims.

We claim:

1. Apparatus of the class described comprising a carrier, a longitudinally extending annular member mounted on said carrier and having its inner end connected to said carrier, an outer die member secured to said annular member adjacent the outer end thereof, a mandrel mounted in said annular member having its inner end connected to said annular member to provide an annular space therebetween, and an inner die member mounted on said mandrel interiorly of said outer die member, said inner die member having a lost motion slidable connection with said mandrel.

2. Apparatus of the class described comprising a carrier, a longitudinally extending annular member mounted around said carrier and having its inner end connected to said carrier, an outer die member secured to said annular member adjacent the outer end thereof, a mandrel mounted in said annular member having its inner end connected to said annular member to provide an annular space therebetween, an inner die member mounted on said mandrel interiorly of said outer die member, said inner die member having a lost motion slidable connection With said mandrel, and means for causing relative movement between a pipe end and said die members to expand the pipe over said inner die by entering the pipe into said annular space, and to reduce the diameter and wall thickness of the expanded pipe by the conjoint action of said die members by Withdrawing the expanded pipe from said annular space.

3. The method of increasing the strength of pipe ends which comprises upsetting the end portion ofa length of pipe while in a heated condition to thicken and taper the walls thereof, cooling said upset end portion below the critical temperature thereof, inserting an internal die member in said upset portion to expand the same while passing an external die thereover in longitudinally offset relation with respect to said inner die member, bringing said die members into telescoped relation and withdrawing the same from said expanded portion to reduce the diameter of said expanded and upset portion by said outer die and to reduce the wall thickness of said portion by the conjoint action of said inner and outer die members. a

4. Apparatus of the class described comprising a carrier, a longitudinally extending annular member mounted on said carrier and having its inner end connected to said carrier, an outer die member secured to said annular member adjacent the outer end thereof, a mandrel mounted in said annular member having its inner end connected to said annular member to provide an annular space therebetween, and an inner die member mounted on said mandrel interiorly of said outer die member, said outer die member having a lost motion slidable connection with said annular member.

CHARLES C. LUCE. NEIL B. DUNCAN. 

